Thermal relay



W. M. BRADSHAW THERMAL RELAY Filed Sept. 23, 192] INVENTOR away 7 1 ATTORNEY WITNESSES:

Patented Oct. 12, 1926.

' umrao STATES P ENT OFFICE.

WILLIAM E. BRADSHAW, OF WILKINSBURG, PENNSYLVANIA, AssIGNoR '10 wns'r- INGEOUSE ELECTRIC a MANUFACTURING COMPANY, A CORPORATION OF PENN- SYLVANIA.

THERMAL RELAY.

Application filed September 23, 1921.

My invention relates to relays and particularly to thermal relays of the cartridge type. T One object of my invention is to provide a thermal relay that shall have means for reinforcing the same to effectively maintain the co-operating portions of the relay in alinement.

Another Object of my invention is to provide a thermal relay employing a bimetallic element that shall not require auxiliary condnctors for connecting the bimetallic elements in series with the ferrules that are dis osed at the respective ends of a casing enc osing the bimetallic element.

A further object of my invention is to provide a relay, of the above-indicated character, in which a bimetallic element and a contact memberto be engaged thereby shall so be disposed at the respective ends of the relay and shall be provided with means for precludinlg a relative movement between the various e ements.

A further Object of my invention is to 95 provide a thermal relay, of the above-indicated character, that shall embody means for permitting Observation and adjustment of the contact member within the casing and for closin the casing to the surrounding air.

A still further object of my invention is to provide a relay of the above-indicated character that shall be simple and inexpensive to construct, easy to assemble, and efiective and reliable in its operation;

In practicing my invention, 1' provide a tubular conductin member, a cylindrical insulating casing t erefor, a bimetallic element and an adjustable contact member that is adapted to be engaged b the bimetallic element. The contact mem er and the bimetallic element are supported by bushings, of molded insulating material, that are securely disposed at the respective ends of the cylindrical insulating casing. The bimetallic element is slitted from opposite ends to increase the resistance thereof and to provide two terminals therefor at one end.

One terminal of the bimetallic element is adapted to be soldered to the tubular conducting member, and the other terminal of the bimetallic element is ada ted to be soldared, or otherwise connecte to one of the end ferrules. The other end ferrule is pro- Serial No. 502,677.

vided with internal threads whereby the ferrule may be screwed upon the other end of the tubular conducting member to effect engagement therewith.

The cylindrical casing of insulating material is disposed around the conducting tubular member between the end ferrules. The casing is slitted to permit it to be readily moved with respect to the conducting member to compensate for high spots on the latter. The tubular conducting member is provided with three apertures opposite the contact member that is to be engaged by the bimetallic element, and the insulating casing is also provided with a single aperture through which, when alined with the apertures in the conducting member, the contact member and the bimetallic element may be observed and adjusted, after which the insulating casing may be further turned to close the. conducting member to the outer air.

Figure l of the accompanying drawings is a perspective view of a thermal relay em bodying my invention, and

Fig. 2 is a plan View, partially in section, of the relay shown in Fig. 1, and

Fig. 3 is a side elevational view of the insulating casing.

The relay comprises, in general, a tubular conducting member 1, a bimetallic element 2 and a stationary supporting member for an adjustable contact member 3, both of which are disposed within the tubular conducting member, two supporting bushings 4 and 5 for the bimetallic element and the contact member, respectively, a cylindrical casing 6 of insulating material and two end ferrules 7 and 8.

The bimetallic element 2 is slitted from the respective ends thereof to constitute a conductor having a relatively long currentconducting path and a relatively small crosssectional area. A greater degree of heating is thus obtained and the relay may be caused to operate by currents of relatively small values.

The bimetallic element is rigidly secured, at one end, by being molded as a unit in the bushing 4 of molded insulati'n material. One terminal 10 of the bimeta ic element 2 is adapted to be fitted into a slot 9 in the tubular member 1 and soldered to said memher whereby rotary movement of the molded bushing t is precluded. The other terminal ll of the bimetallic element is adapted to lit into a slot 12 in the ferrule 7 to be soldered to the same.

The free end of the bimetallic element 2 supports and controls a contact member 13 which is adapted to co-operate with the contact member 3 to control an external auxiliary circuit. The bushing 5 has a small pin 14; dis iosed in the side thereof that is adapted to lit into a slot 15 in the tubular member to prevent relative movement between the bushing and the tubular conducting member 1. it screw 16 is provided to permit the contact member 3 to be connected to an external circuit that is to be controlled thereby.

The end portion 17 of the conducting member 1 is screw-threaded, and the terrule 8 is provided with internal threads whereby the ferrule may be securely mountcd upon the conducting member 1.

The conducting member 1 is also provided with three apertures 18, 19 and 20 whereby the engagement between the contact member 3 and the contact member 13 may be observed and adjusted.

The insulating casing 6 is provided with a single aperture 21 that may be alined with those in the conducting tube 1 to permit observation and adjustment of the contact member within the onducting tube. lVhen the aperture 21 is out of registry with the apertures l8. l9 and 20, the tube is closed to the surrounding air to exclude dust and other foreign particles therefrom. The casing (3 also serves thus to retain the heat within the casing l and to prevent undue dissipation of the heat therefrom.

The casing 6 is slitted, as illustrated in Fig. 3, at an angle with the axis of the tube to permit two degrees of movement when adjusting the casing to compensate for high spots or irregularities on the external sur face of the conducting tubular member 1. The. rising 6 its the tubular member relatively closely and is so held between the ferrules T and 8 that it may be turned to aline the aperture 21 therein with those in th tubular conducting member 1.

By me: is of the construction that I employ and have illustrated. it will be seen that the relay embodying my invention is readily and easily assembled. The various co-operating elements are so arranged as to be e'liectively maintained in alinement. Furthermore, means are provided whereby the relative adjustment of the contact members within the relay may be effected without removing the relay from service or removing it from the ferrules within which it may, at the same time, be disposed.

My invention is not limited to the particular arrangement or structure that is illustrated, since modifications may be made therein within the spirit and scope of the invention, as set forth in the appended claims.

I claim as my invention:

1. A thermal relay comprising a bimetallic element, a metallic casing therefor, an internally threaded ferrule upon one end of the metallic casing, a ferrule disposed at the other end ot the casing and an insulating casing between the latter ferrule and the metallic casing.

The COlIlblllillIlOIl with. a tubular coir ducting member. of a closely litting tube oi insulating material having two degrees of adjustment to compensate for high spots on the tubular conducting member.

3. A thermal relay comprising a cylindrical conducting member having one end thereof externally threaded, a bimetallicelement, a stationary contact member adapted to be engaged thereby, means for securely disposing the bimetallic element and the contact member at the respective ends of the cylindrical member, two end ferrules, one of which is internally threaded to engage the cylindrical conducting member, means whereby the other ferrule may be secured to i one end of the bimetallic element, and a cylindrical casing for the cylindrical conducting member, said casing being relatively movable between the ferrules and the Conducting member.

1-. A thermal relay comprising a cylindrical conducting member having one end thereof externally threaded, a bimetallic element, a stationary contact member adapted to be engaged thereby, means for securely disposing the bimetallic element and the contact member at the respective ends of the cylindrical member, two end ferrules, one of which is internally threaded to be screwed upon the cylindrical conducting member, means whereby the other ferrule may be secured to one end of the bimetallic element, and means co-operating with the conducting member to permit observation and adjustment of the contact member and closing of the conductin member to the surroundii'ig air.

A thermal relay comprising a cylindrical conducting member having one end thereof externally threaded, abimetallic element, a stationary contact member adapted to be engaged thereby, insulating means for supporting the bimetallic element and the contact member at the respective ends of the conducting member and means for precluding relative rotary movement between the conducting member and the supporting means, comprising means for electrically connecting the bimetallic member and the conducting member.

6. A thermal relay comprising a cylindrical conducting member, bushings of electricinsulating materal located in said member, at the respective ends thereof, a stationary contact member supported by the first of said bushings, a longitudinally slitted bimetallic clement supported by the second of said bushings and having one of its ends electrically connected to said conducting member, an end ferrule mounted on one end of said conducting member and in electrical connection therewith, a second ferrule mounted on the other end of said conducting member and having the other end of said bimetallic element electrically connected thereto, and an exterior casing of electricinsulating material on said conducting member and extending between said ferrules.

7 A thermal relay comprising a cylindrical conducting member having a plurality of spaced apertures therein at one end thereof,

two end ferrules, two end bushings, a bimetallic element supported by one of said bushings and having its respective ends electrically connected to one of said ferrules and to said conducting member, astationary contact member supported by the other of said bushings, and a cylindrical casing for the cylindrical conducting member having a single aperture therein and movable relatively to the ferrules and the conducting member to permit registration of the apertures in the casing and the conducting member for permitting of observation and adjustment of the contact member and closing of the conducting member.

In testimony whereof, I have hereunto subscribed my name this 7th day of September, 1921.

WILLIAM M. BRADSHAW. 

